Hypertension, left ventricular hypertrophy, and sudden death

Systemic immune-inflammation index (SII) may be an effective indicator in predicting the left ventricular hypertrophy for patients diagnosed with hypertension

The development of left ventricular hypertrophy (LVH) induced by hypertension is considered a poor prognosis for patients. Similarly, high values of the systemic immune-inflammation index (SII) are correlated with high mortality and morbidity in cardiovascular events. Within this context, our study aimed to detect the association of SII with LVH caused by hypertension. The study included 150 patients diagnosed with hypertension in total and evaluated them as two separate groups with regard to left ventricular mass index (LVMI), including 56 patients (37.3%) with LVH and 94 patients (62.6%) with non-LVH. SII was calculated as platelet × neutrophil/lymphocyte counts. The SII values regarding the group with LVH were detected remarkably higher than those of the non-LVH group (p < 0.001). Additionally, the SII levels of patients with eccentric and concentric hypertrophy were detected higher than those of the normal ventricular geometry and concentric remodeling groups. About curve analysis of the receiver-operating characteristic (ROC), SII values above 869.5 predicted LVH with a sensitivity of 82.1% and specificity of 86.2% (AUC: 0.861; 95% CI: 0.792-0.930; p < 0.001). LVH can be predicted independently through the use of SII in patients diagnosed with hypertension, which may be a simple and easily calculable marker for judging LVH. Moreover, SII can serve as an accurate determinant for the prediction of LVH, in comparison to NLR and PLR.

Cardiac Fibrosis in the Pressure Overloaded Left and Right Ventricle as a Therapeutic Target

Myocardial fibrosis is a remodeling process of the extracellular matrix (ECM) following cardiac stress. "Replacement fibrosis" is a term used to describe wound healing in the acute phase of an injury, such as myocardial infarction. In striking contrast, ECM remodeling following chronic pressure overload insidiously develops over time as "reactive fibrosis" leading to diffuse interstitial and perivascular collagen deposition that continuously perturbs the function of the left (L) or the right ventricle (RV). Examples for pressure-overload conditions resulting in reactive fibrosis in the LV are systemic hypertension or aortic stenosis, whereas pulmonary arterial hypertension (PAH) or congenital heart disease with right sided obstructive lesions such as pulmonary stenosis result in RV reactive fibrosis. In-depth phenotyping of cardiac fibrosis has made it increasingly clear that both forms, replacement and reactive fibrosis co-exist in various etiologies of heart failure. While the role of fibrosis in the pathogenesis of RV heart failure needs further assessment, reactive fibrosis in the LV is a pathological hallmark of adverse cardiac remodeling that is correlated with or potentially might even drive both development and progression of heart failure (HF). Further, LV reactive fibrosis predicts adverse outcome in various myocardial diseases and contributes to arrhythmias. The ability to effectively block pathological ECM remodeling of the LV is therefore an important medical need. At a cellular level, the cardiac fibroblast takes center stage in reactive fibrotic remodeling of the heart. Activation and proliferation of endogenous fibroblast populations are the major source of synthesis, secretion, and deposition of collagens in response to a variety of stimuli. Enzymes residing in the ECM are responsible for collagen maturation and cross-linking. Highly cross-linked type I collagen stiffens the ventricles and predominates over more elastic type III collagen in pressure-overloaded conditions. Research has attempted to identify pro-fibrotic drivers causing fibrotic remodeling. Single key factors such as Transforming Growth Factor β (TGFβ) have been described and subsequently targeted to test their usefulness in inhibiting fibrosis in cultured fibroblasts of the ventricles, and in animal models of cardiac fibrosis. More recently, modulation of phenotypic behaviors like inhibition of proliferating fibroblasts has emerged as a strategy to reduce pathogenic cardiac fibroblast numbers in the heart. Some studies targeting LV reactive fibrosis as outlined above have successfully led to improvements of cardiac structure and function in relevant animal models. For the RV, fibrosis research is needed to better understand the evolution and roles of fibrosis in RV failure. RV fibrosis is seen as an integral part of RV remodeling and presents at varying degrees in patients with PAH and animal models replicating the disease of RV afterload. The extent to which ECM remodeling impacts RV function and thus patient survival is less clear. In this review, we describe differences as well as common characteristics and key players in ECM remodeling of the LV vs. the RV in response to pressure overload. We review pre-clinical studies assessing the effect of anti-fibrotic drug candidates on LV and RV function and their premise for clinical testing. Finally, we discuss the mode of action, safety and efficacy of anti-fibrotic drugs currently tested for the treatment of left HF in clinical trials, which might guide development of new approaches to target right heart failure. We touch upon important considerations and knowledge gaps to be addressed for future clinical testing of anti-fibrotic cardiac therapies.

Relationship between morning blood pressure surge and the frontal plane QRS-T angle in newly diagnosed hypertensive patients

BACKGROUND

Morning blood pressure surge (MBPS) plays an important role in target organ damage and major adverse cardiac events. The frontal QRS-T [f(QRS-T)] angle is the electrocardiographic marker and index of ventricular arrhythmogenic events. We aimed to investigate the relationship between MBPS and the f(QRS-T) angle, which is an indicator of ventricular repolarization disorder, in patients with newly diagnosed HT.

METHODS

Between June 2020 and March 2021, 263 patients with newly diagnosed HT who were admitted to our outpatient clinic were prospectively included in the study. According to ambulatory blood pressure monitoring (ABPM), the patients were categorized into two groups: Group-I: low-value MBPS (<37 mm Hg), and group-II: high-value MBPS (≥37 mm Hg). The f(QRS-T) angle calculated from the 12-lead electrocardiogram and all other data were compared between the groups.

RESULTS

A total of 186 newly diagnosed HT patients who met the inclusion criteria were included in the study. The average f(QRS-T) angle in Groups I and 2 was 21° ± 16° and 51° ± 30°, respectively (P < .001). According to multivariate regression analysis, T peak-end and MBPS were found to be independent predictors of the f(QRS-T) angle.

CONCLUSIONS

As a result of our study, we found that the f(QRS-T) angle was widened in patients with exaggerated MBPS. The cause of increased cardiovascular outcomes in patients with exaggerated MBPS may be explained by widened in the f(QRS-T) angle that is a ventricular repolarization parameter.

Left ventricular hypertrophy and sudden cardiac death

Sudden cardiac death (SCD) is among the leading causes of death worldwide, and it remains a public health problem, as it involves young subjects. Current guideline-directed risk stratification for primary prevention is largely based on left ventricular (LV) ejection fraction (LVEF), and preventive strategies such as implantation of a cardiac defibrillator (ICD) are justified only for documented low LVEF (i.e., ≤ 35%). Unfortunately, only a small percentage of primary prevention ICDs, implanted on the basis of a low LVEF, will deliver life-saving therapies on an annual basis. On the other hand, the vast majority of patients that experience SCD have LVEF > 35%, which is clamoring for better understanding of the underlying mechanisms. It is mandatory that additional variables be considered, both independently and in combination with the EF, to improve SCD risk prediction. LV hypertrophy (LVH) is a strong independent risk factor for SCD regardless of the etiology and the severity of symptoms. Concentric and eccentric LV hypertrophy, and even earlier concentric remodeling without hypertrophy, are all associated with increased risk of SCD. In this paper, we summarize the physiology and physiopathology of LVH, review the epidemiological evidence supporting the association between LVH and SCD, briefly discuss the mechanisms linking LVH with SCD, and emphasize the need to evaluate LV geometry as a potential risk stratification tool regardless of the LVEF.

The frontal plane QRS-T angle may affect our perspective on prehypertension: A prospective study

BACKROUND

The frontal plane QRS-T [f(QRS-T)] angle is an easy marker of myocardial repolarization and was associated with adverse cardiovascular outcomes like prehypertension (PHT). This study was aimed to investigate to evaluate the f(QRS-T) angle in patients with PHT.

METHODS

We measured f(QRS-T) angle of 70 subjects with PHT, 109 patients with hypertension (HT), and 102 normotensive healthy volunteers. The f(QRS-T) angle was calculated from 12-lead electrocardiography.

RESULTS

The f(QRS-T) angle was significantly higher in the HT and PHT groups as compared to the control group, but there was no significant difference in the f(QRS-T) angle between the HT and PHT groups. The f(QRS-T) angle was significantly and positively correlated with age, systolic blood pressure (BP) in 24 hours, average BP in 24 hours, pulse pressure in 24 hours, hemoglobin, QT dispersion, TpE distance while was negatively correlated with left ventricular ejection fraction. In multivariable analysis, we showed that systolic BP, average BP in 24 hours, pulse pressure in 24 hours, hemoglobin, QT dispersion, Tpe distance were independent predictors of higher f(QRS-T) angle.

CONCLUSIONS

The f(QRS-T) angle, a noninvasive measurement analyzing the dysfunction in cardiac conduction system, was increased in subjects with PHT as compared to normotensives, and the subjects with PHT had f(QRS-T) angle as higher as patients with HT did. Our findings are supportive for the hypothesis that disturbances in ventricular repolarization is present in an early stage of essential hypertension.

Beta 1 adrenoceptor blockade promotes angiogenesis in hypertrophied myocardium of transverse aortic constricted mice

Left ventricular hypertrophy (LVH) is an adaptive structural remodelling consequent to uncontrolled blood pressure. Impaired angiogenesis plays a vital role in transiting LVH into cardiac failure. Catecholamines modulate myocardial function through beta adrenoceptors, and their blockers (β-AR) reduce cardiovascular morbidity and mortality by decelerating the LVH progression. Nonetheless, the effect of β-AR blockers on myocardial vascular bed remains largely obscure. Hence, this study is focussed on analysing the possible outcomes of β-AR blockers on myocardial vascular remodelling using a surgically induced LVH mice model. Transverse aortic constricted mice and sham-operated mice were administered with metoprolol at a dose of 30 mg/kg/d for 60 days and myocardial vascular endothelial growth factor (VEGF) alpha levels, GSH/GSSG ratio, myocardial protein carbonyl content, hypertrophy index and global myocardial function, trans-aortic fluid dynamics and expression pattern of angiopoietin-1 and VEGF alpha were assessed. These findings were further confirmed by histochemical analysis for myocardial capillary density, perivascular fibrosis ratio and intimal thickening. Sub- chronic β-AR blockade reduced the oxidative stress, hypertrophic index, intimal thickening and perivascular fibrosis ratio. A marked increase in myocardial VEGF, angiopoietin 1, global myocardial function and myocardial capillary density was also observed. There was a reduction in the LVH and upregulation of myocardial angiogenesis concluding that β-AR blockers prevent adverse vascular remodelling which might underlie its concealed mechanism of action.

Medical conditions in scuba diving fatality victims in Australia, 2001 to 2013

INTRODUCTION

This study identified pre-existing medical conditions among scuba diving fatalities in Australia from 2001 to 2013, inclusive, and assessed whether these conditions likely contributed to the deaths.

METHODS

The National Coronial Information System (NCIS) was searched for scuba diving-related cases during 2001-2013, inclusive. Coronial findings, witness and police reports, medical histories, and autopsy and toxicology reports were scrutinised for pre-existing medical conditions and autopsy findings. Predisposing factors, triggers, disabling agents, disabling injuries and causes of death were analysed using a validated template.

RESULTS

There were 126 scuba diving-related fatalities identified during the study period. Forty-six (37%) divers were identified as having a significant medical condition which may have contributed to their incident. The most common condition was ischaemic heart disease (IHD) which had been diagnosed in 15 of the divers. Thirty-two (25%) deaths were attributed to cardiac disabling injuries (DI) such as ischaemic heart disease and arrhythmias, although a cardiac DI was thought likely in another six. Respiratory conditions were implicated in eight (6%) deaths, at least four associated with cerebral arterial gas embolism. At least 14 (11%) divers who had contributory pre-existing medical conditions had been cleared to dive by a medical practitioner within the year prior.

CONCLUSIONS

Chronic health-related factors played a major role in almost half of these deaths; primarily cardiac conditions such as IHD and cardiac arrhythmias. Although fitness-to-dive (FTD) assessments have limitations, the high incidence of cardiac-related deaths indicates a need for 'older' divers to be medically assessed for FTD.

NLR-A Simple Indicator of Inflammation for the Diagnosis of Left Ventricular Hypertrophy in Patients with Hypertension

We aimed to investigate the relationship between neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP), brain natriuretic peptide (BNP), and left ventricular hypertrophy (LVH) in hypertension.

METHODS

This study included 386 patients with hypertension. Mann-Whitney U test and multivariate binary logistic regression analysis were used to investigate the relationship between NLR, CRP, BNP, and LVH in patients with hypertension, as well as compare the levels of NLR, CRP, and BNP in the four configurations. Receiver operator characteristic (ROC) curve was used to compare the diagnostic efficacy of NLR, CRP, and BNP on LVH.

RESULTS

The NLR and CRP and BNP levels of the LVH group were significantly higher than those of the non-LVH group. In the multivariate logistic regression analysis, NLR as well as age, BMI, and SBP were associated with LVH. In addition, in patients with eccentric and concentric hypertrophy, the NLR and CRP and BNP levels were higher than those of the normal left ventricular geometry and concentric remodeling groups. The cutoff values of NLR, CRP, and BNP obtained by ROC curve were 2.185, 2.205, and 283.45, respectively, for the prediction of LVH.

CONCLUSIONS

NLR is independently associated with LVH in patients with hypertension, and this is consistent with the diagnostic efficacy of CRP and BNP, which may be a simple and convenient indicator for judging LVH.

The Potential Role of Circulating Endothelial Cells and Endothelial Progenitor Cells in the Prediction of Left Ventricular Hypertrophy in Hypertensive Patients

Background

The main aim of present study is to evaluate the potential role of circulating endothelial cells (CECs) and endothelial progenitor cells (CEPCs) – representing specific markers of endothelial damage, in the prediction of left ventricular hypertrophy (LVH) in hypertensive patients categorized into two groups; mild (MH) and resistant hypertension (RH).

Materials and Methods

Thirty patients with MH and 28 subjects with RH were involved in the study. In both groups, patients were divided into an LVH and non-LVH group. The control group included 33 age and sex-matched normotensive volunteers. Physical examination, laboratory tests and echocardiography were conducted.

Results

In both the MH and RH group, patients with as well as without LVH demonstrated a higher number of CECs and a lower ratio of CEPCs/CECs as compared to the healthy control. Multiple linear regression analysis showed a positive association of CEPCs with left ventricular mass (LVM) and left ventricular mass index (LVMI), independently of other confounders.

Conclusion

Our results suggest that endothelial injury observed as an elevated CECs number and its impaired regeneration, reflected by a lowered CEPCs/CECs ratio, precede LVH occurrence and may play a significant role in LVH development regardless of the clinical severity of hypertension. Moreover, independent correlation of CEPCs with echocardiographic (ECG) incidences of LVH suggests their potential use as a screening biomarker to stratify the risk of LVH development.

The hemodynamic effects of a central iliac arteriovenous anastomosis at 6 months in patients with resistant and uncontrolled hypertension

A central iliac arteriovenous anastomosis, termed the "coupler" (ROX Medical), results in a significant reduction in blood pressure (BP) in hypertensive patients. This study assessed functional and hemodynamic changes induced by the device. Twenty-one patients with resistant and/or uncontrolled hypertension underwent stress echocardiography and cardiopulmonary exercise testing (CPET) at baseline and 6 months post-coupler implantation. End points were selected to best evaluate cardiac function including Doppler stroke volume (SV), septal and lateral E/E', and right ventricular systolic velocity S' (RV S'). CPET VO₂ peak demonstrated total cardiopulmonary performance. SV increased from 76.4 SD12.2 mL to 92.1 SD22.7 mL 6 months post-coupler insertion; P = .002. No changes in RV S', septal or lateral E/E', or VO₂ peak were observed. Five patients experienced increased diuretic requirement ≥3 times baseline. RV S' fell from 19.0 SD1.87 cm/s to 16.80 SD3.43 cm/s in these patients (P > .05). A significant increase in SV 6 months post-coupler insertion was observed. In patients with increased diuretic requirement, the device was associated with a lower RV S' suggesting occult RV dysfunction as the mechanism of this pre-specified adverse outcome.

Superior Hypertension Management in Pediatric Kidney Transplant Patients After Native Nephrectomy

BACKGROUND

Native nephrectomy in pediatric kidney transplant recipients is performed for multiple indications. Posttransplant hypertension requiring medical management is common, and the effect of native nephrectomy on posttransplant hypertension is poorly studied. Our aim is to evaluate the impact of native nephrectomy on posttransplant hypertension.

METHODS

One hundred thirty-six consecutive pediatric kidney transplant recipients from 2007 to 2012 were studied at a single institution and divided into 2 groups: no nephrectomy and native nephrectomy (unilateral and bilateral nephrectomy). Antihypertensive medication use was evaluated before nephrectomy/transplant, at discharge from transplant and at 1, 3, and 5 years posttransplant.

RESULTS

In a bivariate analysis, nephrectomy was associated with a significant reduction in the percentage of patients requiring antihypertensive medication at the time of discharge (27.3%) and 1 year posttransplant (10.7%) as compared with patients without nephrectomy (71.7%, and 50%, respectively, P < 0.05). This trend toward reduction in antihypertensive medication in the nephrectomy group as compared with the no nephrectomy group persisted at 3 (18.6% versus 43.2%) and 5 years (19.7% versus 37.5%) posttransplant. Multivariable logistic regression demonstrated that patients without native nephrectomy had higher odds of requiring antihypertensive medication at the time of discharge (3.3) and 1 year (5.2) as compared with patients who underwent native nephrectomy (P = 0.036 and P = 0.013, respectively).

CONCLUSIONS

Native nephrectomy reduces the odds of needing antihypertensive medication after transplant. The impact of native nephrectomy is crucial to the comprehensive management of pediatric transplant recipients where medication compliance is challenging and lifelong hypertension is known to negatively impact cardiovascular health.

Association of histamine with hypertension-induced cardiac remodeling and reduction of hypertrophy with the histamine-2-receptor antagonist famotidine compared with the beta-blocker metoprolol

The association of histamine with adverse cardiac remodeling in chronic pressure overload has not received much attention. A pilot study in spontaneously hypertensive rats (SHRs) indicated a reduction of left ventricular hypertrophy (LVH) with a histamine-2-receptor (H2R) antagonist (famotidine). This finding prompted a detailed investigation of temporal variation in myocardial histamine and H2R expression and the cardiovascular response to H2R antagonism compared with that of the conventional beta-blocker metoprolol. Reduction of LVH is known to reduce the risk of adverse cardiovascular events. The myocardial histamine content and H2R expression increased with age in SHRs but not in normotensive Wistar rats. The cardiovascular response to famotidine (30 mg kg^-1) was compared with that of metoprolol (50 mg kg^-1) in 6-month-old male SHRs treated for 60 days. The decrease in diastolic blood pressure and improvement in cardiac function induced by famotidine and metoprolol were comparable. Both treatments caused the regression of LVH as assessed from the hypertrophy index, histomorphometry, B type natriuretic peptide (BNP), pro-collagen 1, and hydroxyproline levels. Calcineurin-A expression (marker of pathological remodeling) decreased, and Peroxiredoxin-3 expression (mitochondrial antioxidant) increased in response to the treatments. The myocardial histamine levels decreased with the treatments. The age-dependent increase in myocardial histamine and H2R in the SHRs signifies their association with progressive cardiac remodeling. The regression of LVH and improvement in cardiac function by famotidine further demonstrates the role of histamine in cardiac remodeling. Hypertrophy of cultured cardiac cells upon exposure to histamine and the H2R agonist amthamine substantiates the role of histamine in cardiac remodeling. The cardiovascular response to famotidine is comparable to that of metoprolol, suggesting repurposing of H2R antagonists for the management of hypertensive heart disease.

Provisional report on diving-related fatalities in Australian waters in 2012

INTRODUCTION

An individual case review of known diving-related deaths that occurred in Australia in 2012 was conducted.

METHOD

The case studies were compiled using statements from witnesses and reports of the police and coroners. In each case, the particular circumstances of the accident and details from the post-mortem examination, where available, are provided.

RESULTS

There were 26 reported fatalities (four less than the previous year). Only two of the victims were female (one snorkeller and one scuba diver). Fourteen deaths occurred while snorkelling and/or breath-hold diving, 11 while scuba diving and one diver died while using surface supplied breathing apparatus in a commercial pearl diving setting. Two breath-hold divers likely drowned as a result of apnoeic hypoxia. Cardiac-related issues were thought to have contributed to the deaths of at least three and possibly seven snorkellers and four scuba divers.

CONCLUSIONS

Pre-existing medical conditions; poor organisation, planning and supervision; equipment-related problems; snorkelling or diving alone or with loose buddy oversight and apnoeic hypoxia were features in several deaths in this series.

Left Ventricular Hypertrophy – the Problem and Possible Solutions

Left ventricular hypertrophy (LVH), which describes pathological changes in cardiac structure, is a powerful and reversible predictor of cardiovascular risk. There is a continuous relationship between left ventricular mass (LVM) and the likelihood of cardiovascular events, with no cut-off between the absence of such events and heightened risk. A correlation between LVH and blood pressure is well established. There is a paradox, however, that the structural changes to the heart as a result of increased workload due to high blood pressure appear to promote cardiovascular disease. This may be partially explained by the fact that ambulatory blood pressure measurements correlate more closely with LVH than resting blood pressure. Blood pressure variation throughout the day is also emerging as an important correlate of LVH, and a strong association has been identified between an early morning rise in blood pressure and increased LVM. Use of anti-hypertensive agents not only lowers blood pressure, but can also bring about LVH regression. The pathological role of angiotensin II in LVH and target-organ damage within the cardiovascular continuum suggest that agents targeting the renin – angiotensin - aldosterone system (RAAS), such as the angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, may prove particularly effective and may confer beneficial effects in addition to the lowering of blood pressure. The angiotensin II receptor blockers may be very appropriate treatment options because of their placebo-like tolerability and the possibility of more complete blockade of the RAAS. Within this class of anti-hypertensive agents, pharmacological differences may mean that some agents afford greater cardioprotection than others.

Sudden cardiac death and chronic kidney disease: From pathophysiology to treatment strategies

Chronic kidney disease (CKD) patients demonstrate higher rates of cardiovascular mortality and morbidity; and increased incidence of sudden cardiac death (SCD) with declining kidney failure. Coronary artery disease (CAD) associated risk factors are the major determinants of SCD in the general population. However, current evidence suggests that in CKD patients, traditional cardiovascular risk factors may play a lesser role. Complex relationships between CKD-specific risk factors, structural heart disease, and ventricular arrhythmias (VA) contribute to the high risk of SCD. In dialysis patients, the occurrence of VA and SCD could be exacerbated by electrolyte shifts, divalent ion abnormalities, sympathetic overactivity, inflammation and iron toxicity. As outcomes in CKD patients after cardiac arrest are poor, primary and secondary prevention of SCD and cardiac arrest could reduce cardiovascular mortality in patients with CKD.

Sudden cardiac death in CKD patients

The risk of sudden cardiac death (SCD) is high in chronic kidney disease patients, and it increases with the progression of kidney function deterioration. The most common causes of SDC are the following: ventricular tachycardia, ventricular tachyarrhythmia, tachycardia torsade de pointes, sustained ventricular fibrillation and bradyarrhythmia. Dialysis influences cardiovascular system and results in hemodynamic disturbances as well as electrolyte shifts altering myocardial electrophysiology. Studies suggest that this procedure exerts both detrimental (poor volume control can exacerbate hypertension and left ventricle hypertrophy) and beneficial effects (associated with fluid removal and subsequent decrease in left ventricle stretch). Dialysis-related vulnerability to serious arrhythmias is the result of sudden shifts in fluid status and electrolytes, particularly potassium, which alter the physiological milieu. Also Ca(2+) ions, in which concentration alters during dialysis, are of key importance in the contraction of vascular smooth muscle cells and cardiac myocytes, thus exerting significant effects on hemodynamics. Due to the fact that SCD occurs with similar frequency in peritoneal dialysis and in hemodialysis patients, it seems that end-stage renal disease factors are more important than the specific ones associated with dialysis type. The results of randomized trials suggested that hemodialysis patients may not derive the same benefit of cardiovascular disease therapy including beta-blockers, calcium channel blockers and angiotensin-converting enzyme inhibitors as the general population with normal kidney function. Noninvasive tests used to stratify SCD risk in HD patients have poor positive value, and thus, combining tests including HRV, baroreceptor sensitivity and effectiveness index as well as its function indices and heart rate turbulence should be implemented. There are only few large randomized placebo-controlled trials assessing the influence of cardioprotective medications or implantable cardioverter defibrillator (ICD) implantation in dialysis patients on life quality and survival, and their results are sometimes contradictory. The decision concerning treatment and/or ICD implantation in this group of patients should be made on the basis of careful assessment of individual risk factors. Moreover, due to the high hazard of cardiovascular mortality including SCD in dialysis patients, physicians should concentrate on the early selection of high-risk patients, monitoring them and introduction of preventive measures.

Kinetics of a single cross-bridge in familial hypertrophic cardiomyopathy heart muscle measured by reverse Kretschmann fluorescence

Familial hypertrophic cardiomyopathy (FHC) is a serious heart disease that often leads to a sudden cardiac death of young athletes. It is believed that the alteration of the kinetics of interaction between actin and myosin causes FHC by making the heart to pump blood inefficiently. We set out to check this hypothesis ex vivo. During contraction of heart muscle, a myosin cross-bridge imparts periodic force impulses to actin. The impulses are analyzed by fluorescence correlation spectroscopy (FCS) of fluorescently labeled actin. To minimize observation volume and background fluorescence, we carry out FCS measurements in surface plasmon coupled emission mode in a reverse Kretschmann configuration. Fluorescence is a result of near-field coupling of fluorophores excited in the vicinity of the metal-coated surface of a coverslip with the surface plasmons propagating in the metal. Surface plasmons decouple on opposite sides of the metal film and emit in a directional manner as far-field p-polarized radiation. We show that the rate of changes of orientation is significantly faster in contracting cardiac myofibrils of transgenic mice than wild type. These results are consistent with the fact that mutated heart muscle myosin translates actin faster in in vitro motility assays.

Single molecule kinetics in the familial hypertrophic cardiomyopathy D166V mutant mouse heart

One of the sarcomeric mutations associated with a malignant phenotype of familial hypertrophic cardiomyopathy (FHC) is the D166V point mutation in the ventricular myosin regulatory light chain (RLC) encoded by the MYL2 gene. In this report we show that the rates of myosin cross-bridge attachment and dissociation are significantly different in isometrically contracting cardiac myofibrils from right ventricles of transgenic (Tg)-D166V and Tg-WT mice. We have derived the myosin cross-bridge kinetic rates by tracking the orientation of a fluorescently labeled single actin molecule. Orientation (measured by polarized fluorescence) oscillated between two states, corresponding to the actin-bound and actin-free states of the myosin cross-bridge. The rate of cross-bridge attachment during isometric contraction decreased from 3 s(-1) in myofibrils from Tg-WT to 1.4 s(-1) in myofibrils from Tg-D166V. The rate of detachment decreased from 1.3 s(-1) (Tg-WT) to 1.2 s(-1) (Tg-D166V). We also showed that the level of RLC phosphorylation was largely decreased in Tg-D166V myofibrils compared to Tg-WT. Our findings suggest that alterations in the myosin cross-bridge kinetics brought about by the D166V mutation in RLC might be responsible for the compromised function of the mutated hearts and lead to their inability to efficiently pump blood.

Elevated blood pressure and electrocardiographic frontal T axis and spatial QRS-T angle changes in postmenopausal women

INTRODUCTION

Frontal T axis and spatial QRS-T angle are both measures of disturbances in ventricular repolarization and depolarization. We determined whether increased blood pressure is a risk factor for changes in these parameters in postmenopausal women free of left ventricular hypertrophy.

MATERIALS AND METHODS

This cross-sectional study included 969 women. A standard 12-lead electrocardiogram (ECG) was recorded, and frontal T axes and spatial QRS-T angles were computed from vectorcardiography. Logistic regression analysis was used to assess the relationship between systolic and diastolic blood pressures on the one hand and both ECG parameters on the other.

RESULTS

Odds ratios were 1.08 (95% confidence interval [CI], 0.99-1.18) and 1.12 (95% CI, 1.03-1.23) per 10 mm Hg systolic blood pressure for frontal T axis and QRS-T angle, respectively. These values were 1.05 (95% CI, 0.95-1.16) and 1.12 (95% CI, 1.02-1.23) per 5 mm Hg diastolic blood pressure for frontal T-axis and QRS-T angle, respectively.

CONCLUSION

Elevated blood pressure may lead to ventricular depolarization and repolarization disturbances before overt ECG left ventricular hypertrophy has developed.

Hypertensive heart disease: effects of lifestyle modifications and antihypertensive drug treatment

Target-organ protection in hypertensive patients has become increasingly important. This review will focus on hypertensive heart disease that is mainly characterized by myocardial hypertrophy and increased interstitial fibrosis. Cardiac remodeling develops as an adaptive response but actually represents a powerful independent risk factor for cardiovascular morbidity and mortality. The review will begin with a brief discussion on the complex pathophysiology of hypertensive cardiac remodeling and its clinical consequences. The effects of nonpharmacologic and pharmacologic antihypertensive treatments on the development and progression of hypertensive heart disease are presented. Finally, the impact of the regression of myocardial hypertrophy and fibrosis on cardiac function and cardiovascular risk are discussed.

From vulnerable plaque to vulnerable patient--Part III: Executive summary of the Screening for Heart Attack Prevention and Education (SHAPE) Task Force report

Screening for early-stage asymptomatic cancers (eg, cancers of breast and colon) to prevent late-stage malignancies has been widely accepted. However, although atherosclerotic cardiovascular disease (eg, heart attack and stroke) accounts for more death and disability than all cancers combined, there are no national screening guidelines for asymptomatic (subclinical) atherosclerosis, and there is no government- or healthcare-sponsored reimbursement for atherosclerosis screening. Part I and Part II of this consensus statement elaborated on new discoveries in the field of atherosclerosis that led to the concept of the "vulnerable patient." These landmark discoveries, along with new diagnostic and therapeutic options, have set the stage for the next step: translation of this knowledge into a new practice of preventive cardiology. The identification and treatment of the vulnerable patient are the focuses of this consensus statement. In this report, the Screening for Heart Attack Prevention and Education (SHAPE) Task Force presents a new practice guideline for cardiovascular screening in the asymptomatic at-risk population. In summary, the SHAPE Guideline calls for noninvasive screening of all asymptomatic men 45-75 years of age and asymptomatic women 55-75 years of age (except those defined as very low risk) to detect and treat those with subclinical atherosclerosis. A variety of screening tests are available, and the cost-effectiveness of their use in a comprehensive strategy must be validated. Some of these screening tests, such as measurement of coronary artery calcification by computed tomography scanning and carotid artery intima-media thickness and plaque by ultrasonography, have been available longer than others and are capable of providing direct evidence for the presence and extent of atherosclerosis. Both of these imaging methods provide prognostic information of proven value regarding the future risk of heart attack and stroke. Careful and responsible implementation of these tests as part of a comprehensive risk assessment and reduction approach is warranted and outlined by this report. Other tests for the detection of atherosclerosis and abnormal arterial structure and function, such as magnetic resonance imaging of the great arteries, studies of small and large artery stiffness, and assessment of systemic endothelial dysfunction, are emerging and must be further validated. The screening results (severity of subclinical arterial disease) combined with risk factor assessment are used for risk stratification to identify the vulnerable patient and initiate appropriate therapy. The higher the risk, the more vulnerable an individual is to a near-term adverse event. Because <10% of the population who test positive for atherosclerosis will experience a near-term event, additional risk stratification based on reliable markers of disease activity is needed and is expected to further focus the search for the vulnerable patient in the future. All individuals with asymptomatic atherosclerosis should be counseled and treated to prevent progression to overt clinical disease. The aggressiveness of the treatment should be proportional to the level of risk. Individuals with no evidence of subclinical disease may be reassured of the low risk of a future near-term event, yet encouraged to adhere to a healthy lifestyle and maintain appropriate risk factor levels. Early heart attack care education is urged for all individuals with a positive test for atherosclerosis. The SHAPE Task Force reinforces existing guidelines for the screening and treatment of risk factors in younger populations. Cardiovascular healthcare professionals and policymakers are urged to adopt the SHAPE proposal and its attendant cost-effectiveness as a new strategy to contain the epidemic of atherosclerotic cardiovascular disease and the rising cost of therapies associated with this epidemic.

The Cardiometabolic Syndrome and Cardiovascular Disease

The cardiometabolic syndrome is a prevalent metabolic disorder. Epidemiologic studies correlate the cardiometabolic syndrome with an increased risk of coronary heart disease, ischemic stroke, cardiovascular mortality, and total mortality. There is also evidence that the cardiometabolic syndrome is a risk factor for abnormalities in myocardial metabolism, cardiac dysfunction, and arrhythmias such as atrial fibrillation. Multiple imaging modalities, both invasive and noninvasive, may help physicians better define the presence or risk of cardiovascular disease in their patients with the cardiometabolic syndrome.

Echocardiographic changes in patients with malignant phase hypertension: the West Birmingham Malignant Hypertension Register

In order to study the echocardiographic abnormalities in consecutive patients with malignant phase hypertension (MHT), we reviewed echocardiograms of 31 patients (23 male; mean age 52+/-14 years) with MHT who were admitted to our unit. Trans-thoracic echocardiography was carried out in all patients, and echocardiographic measurements were compared with those of 39 patients (30 male; mean age 54+/-10 years) with controlled nonmalignant essential hypertension, and 32 (19 male; mean age 51+/-10 years) healthy normotensive volunteers. Patients with MHT had a significantly higher mean systolic and diastolic blood pressure (P<0.001) compared to the other two groups. MHT patients had significantly greater mean left atrial dimensions (P=0.002), as well as aortic root dimensions (P=0.01) and left ventricular (LV) dimensions (with the exception of the diastolic internal diameter) (P<0.001). MHT patients also had a mean larger LV mass and LV mass index (both P<0.001) when compared to the other two groups. The mean ejection fraction was also lower in the MHT group (P<0.001). In conclusion, patients with MHT have significant cardiac hypertrophy, in association with systolic dysfunction and dilated left atria, irrespective of the duration of known hypertension. These abnormalities may predispose MHT patients to cardiovascular complications including heart failure and cardiac arrhythmias, such as atrial fibrillation.